Catheter ablation is an arrhythmia treatment method of inserting an ablation catheter into a cardiac chamber and applying heat between a tip electrode and a counter electrode plate to ablate a myocardial tissue. The catheter ablation is conducted mainly for treatment of tachyarrhythmia such as a paroxysmal supraventricular tachycardia, an atrial tachycardia, an atrial flutter, and a paroxysmal ventricular tachycardia and is a technique of diagnosing a pathogenetic mechanism and a genesis region of an arrhythmia in a cardiac electrophysiological test, thereafter making an electrode of an ablation catheter reach the genesis region of the arrhythmia from the interior of a cardiac chamber, and repeating an operation of applying the electrode to a causative myocardial tissue in the region and heating the tissue at 53 to 60° C. for approximately 60 seconds.
Since many of the ablation catheters currently in use have a metallic electrode having a length of 4 to 8 mm and a diameter of 2 to 3 mm at a tip portion of a catheter shaft, each of such catheters generally adopts a technique of bringing the metallic electrode into contact with a myocardial tissue that causes an arrhythmia in a dotted manner and forming an ablation line while moving the electrode little by little to isolate the source of the arrhythmia (Patent Literature 1).
However, the ablation catheter having the metallic electrode requires several dozen times of repeated ablations to form the ablation line and isolate the source of the arrhythmia and thus causes problems of a prolonged operation and a heavy burden imposed on a patient. Also, since the small metallic electrode needs to be brought into contact with the target region of the myocardial tissue accurately to form the ablation line with the ablation catheter, a physician requires an advanced technique to manipulate the ablation catheter. Further, since the myocardial tissue is ablated in the dotted manner, an insufficient ablation line with spaces between the ablated parts may be formed, in which case the source of the arrhythmia cannot be isolated completely, which may cause recurrence of the arrhythmia.
Recently, an ablation catheter with a balloon having a balloon at the tip of a catheter shaft has been developed, and an ablation catheter system with a balloon including a radio-frequency generating device and a balloon surface temperature uniforming device has been reported (Patent Literatures 2 and 3).
The ablation catheter system with a balloon is a system of expanding a balloon fixed to the tip of a catheter by a liquid for heating and heating the liquid for heating by a radio-frequency current supplied from a radio-frequency generating device to ablate the entire myocardial tissue contacting the surface of the balloon. The temperature of the balloon surface is adjusted by a balloon surface temperature uniforming device such as a vibration imparting device, which imparts a vibration to the liquid for heating filled in the balloon, and is controlled by a temperature sensor arranged in the balloon.